1. Field of the Invention
The invention relates to a structure for supporting a ceramic susceptor.
2. Related Art Statement
In applications such as semiconductor production system, it is demanded to fix a ceramic heater made of, for example, aluminum nitride, onto the inner wall surface of a chamber. It has been tried to fix one end of a tubular supporting portion made of a ceramic plate onto a joining face of a ceramic heater and to the other end of the supporting portion onto the inner wall surface of the chamber. The supporting portion is formed of a heat resistive ceramic plate such as alumina or aluminum nitride. The supporting portion and chamber are sealed in air tight manner with an O-ring. It is thus possible to seal the inner space of the supporting portion from the inner space of the chamber to prevent the leakage of a gas in the inner space of the chamber to the outside of the chamber.
When the tubular supporting portion is joined with the back face of a ceramic heater and the temperature of the heater is elevated, however, fine cracks may be generated from the joining face of the heater to the supporting portion to induce gas leakage. The assignee filed a Japanese Patent publication 2001-250, 858A and disclosed a supporting portion having a shape of bellows joined with a ceramic heater, for providing a solution to the above problems.